SG Chem 2 - Eighth Blog

The last two weeks in chem 2a we did a lot of labs and worksheets to help us get a better understanding of this new unit, unit seven. We also reviewed the unit six material due to the fact that most kids did not seem to understand the material. 

To start learning lesson seven we did a nail lab which required us to mix a copper chloride solution and, in my groups case, one nail (some tables had two or three nails). The goal was to find the ratio of copper produced to iron consumed.

Day 1: The copper chloride before adding 50mL of distilled water

Day 1: Copper Chloride with 50mL of distilled water

Day 1: Nail added to copper chloride solution

Day 2: The nail in the copper chloride 

Day 2: Draining the copper chloride (our nail fully dissolved)

This lab was done over the course of three days and on the third day we took all the information and compared it to the other groups data. We found that for all the groups, no matter how many nails they had, the ratio for moles of copper:moles iron was 1:1.   

That same week we started practicing balancing chemical reactions. A key piece of information from this was that to balance these reactions you needed to balance the amount of atoms, not the number of coefficients. We did a lot of different practice sheets on balancing equations and I think after the first few sheets I was able to get the hang of balancing the equations. Some took longer than others, but I really enjoy these types of problems because it's like a logic puzzle.

Later we did another lab called Describing Chemical Reaction. For this there were about 10 stations that we rotated around to complete a different task. We would observe the reaction between two different chemicals and then later would balance the equations out. I found that lab a lot of fun because there were so many different things to do and all of them were slightly different yet all showed the same basic idea - that when two elements react they may change form but the amount of each elements atoms will stay the same from beginning to the end.

The last two weeks I felt like I really understood the material. Balancing reactions was pretty simple, even though some were more complex than others, the labs were fun and informing, and the class discussions helped to reiterate some of the ideas from unit 6. Something that I did not understand was the patterns of chemical reaction. This was a sheet that we started Friday of this week so it is a rather new concept. We have not been able to talk as a class about these so I'm hoping that that will be able to explain some things to me. I don't understand the differences between some of them or what the point of them are. Overall I think I'd rate my understanding of the past two weeks as a 9/10 just because I understood everything but that patterns in chemical reactions.

SG Chem - Seventh Post

This week in chem 2 we learned the rules to naming ionic and molecular compounds in preparation for the upcoming test. On Monday we were given a packet of paper that gave us the charges for selected elements on the periodic table. We then had to use that information to make observations about certain charges and then solve problems that were given to us.

Periodic table with selected element charges 

We realized that all the elements in column one, or the column closest to the left, have a positive charge of one. If you move one to the right you'll see all the elements have a positive two charge, increasing by one. This is similar to the columns on the very right, where all the elements have a  charge of negative one and when you move one column inward you'll see that each element has a charge of negative two, increasing by a charge of negative one. We made simple observations like this to help us understand and remember which elements had which type of charge. This sheet taught us that to write the formula for the given ionic compound we needed the charges of both elements to balance out to zero. 

Once we got an understanding of what the charges for single elements were we started learning about polyatomic ions, these are ions with multiple elements that create one type of charge. For example, nitrate is a polyatomic ion that consists of one nitrogen and three oxygen. Although there are two elements, oxygen (with a charge of negative two) and nitrogen (with a charge of negative 3) they are bonded together giving the entire ion (NO3) a charge of negative one. Another thing that is important to mention is that poly-atomic ions only consist of multiple non-metals, poly-atomic ions do not contain metals. 

Up to this day we only had learned about elements and compound containing metals, but on Thursday we were introduced to compounds that do not include metals, these are called molecular ions. When this happens you use prefixes such as mono, di, tri, etc. to tell how many atoms of each element there are. For example for ClF5 would be named Chlorine pentafluoride because there is one chlorine atom and five fluoride's. Because fluorine is the second element the name would switch to ending with "ide" and because chlorine is the first element and only has one atom you would not use the prefix "mono." But if the formula is Cl2O then is would be dichloride monoixde because chloride now has two atoms. 

This week I participated a decent amount. I helped my table when we were doing class review but I did not take initiative when writing anything down. I think I could do more to help my table mates such as writing on the board and speaking up in class. I also feel like after reviewing in and out of class I really understood this material. I found it helped me to take extra notes in my journal to emphasize important points that I forgot. Because I felt I had a good understanding of the lessons I tried to help some people from other classes who needed my help understanding the differences in naming ionic and molecular compounds. 

I still need to work on understanding J.J. Thomson's conclusion that because the cathode rays must be stuck together they must be negative. I wasn't really sure how he came to that conclusion or what it meant/what its importance was. A question I still have is how is this information relevant to everything else we learned this week?

I would rank my understanding of this week as a nine out ten because for the most part I understood the rules for each type of ion and how to apply that to solving actual problems. Yet there were still concepts that didn't deal with naming that still confuse me.

SG Chem - Sixth Post

This week in chem 2 we started learning a new unit and to do this we did a lot of experiments. We did the sticky tape lab, the conductivity lab, and the "u" tube lab. I think my favorite lab was the Sticky Tape lab, which was a way for us to understand the interaction between positive, negative, and neutral charges. We started by taking two pieces of tape, placing one on top of another and then quickly pulling them apart to give them a charge. Then we hung them up next to a strip of paper and foil. We created another set of charged tape and then we tested the reaction between the hanging charged tapes (top and bottom), paper, and foil.

The hanging foil and paper before tape is charged 

The process of charging the tape
Right before separating the top and bottom pieces of tape

The hanging foil, paper, and two charged tapes
The two tapes were moving slightly because of their attraction to one another

The top tape had a positive charge while the bottom tape had a negative one. When tested against the foil, paper, and another set of top and bottom tapes we found that each tape attracted the foil, the paper and it's opposite charged tape, but it repelled against it's same charge (i.e. positive repelled positive, negative repelled negative). We also observed that when the two tapes were together, they had neither a positive nor a negative charge because they weren't attracted to anything. This must've meant that the two tapes had the same amount of electrons but when separated, the amount of electrons became uneven. We came to this theory because the two tapes (positive and negative) were now attracted to each other compared to before we put them together to create the charge. We discussed this as a class and came to the conclusion that the electrons became uneven NOT when the two tapes were pulled apart, but rather when the two tapes were put together. Somehow at that point some electrons "jumped" from one piece of tape to another, creating unbalanced amounts on each piece of tape. This is what created the attraction and repulsion between the two tapes.

I really liked this week in chem because we got to do so many things, and each class was very interesting. Something I'm still struggling with is understanding what our "u"tube lab helped us learn. I think that it's partially I'm forgetting because it's new information. I remember going over it on Friday, but because I didn't take a picture or notes, I can't remember exactly what it taught us. Another thing I don't fully understand is how you know how many electrons switch on the two tapes in the sticky tape lab. For the post lab we took notes and I have the amount of electrons switching from a three positive three negative, to a two positive four negative and I don't understand how you'd know that only one electron switches. 

I think my participation was pretty good this week. I helped with the labs, and asked my table mates questions. I think what I need to improve on is asking for help until I understand the concept, because I'll ask once or twice, but I feel bad for asking too many times, so if I don't understand I'll just leave it, which is bad because then I can't learn it. I need to work on the persistence to find the answers in a way that makes sense to me. Because of that, and the fact that some of the post lab things confused me slightly, I would rank my understanding of these week as a 6/10. 

SG Chem 2 - Fifth Blog

This week in Chem 2 we really didn't do any experiments, instead we did a lot of reviewing for the test that was this Friday. On Monday we took a quiz that measured our understanding of how to convert moles to grams, grams to moles, and moles to atoms.

On Tuesday we learned/reviewed how to find the empirical formula when we were given the amount, in grams, of certain elements. Then we learned how to find the molecular formula of the compound after we found the empirical formula. At first I didn't understand how to get the number you multiply the empirical formula by to get the molecular formula, but after going through an example I figured out how to do it. I really like doing this type of problem because the math makes sense to me.

Thursday we worked on a review sheet. It was good to go over the review guide as a class because it helped me get a better understanding of everything, while also jogging my memory on how to solve certain problems. For example this problem on the Chemistry - Unit 5 Review:

The Chemistry Unit 5 Review Question 3
It wants us to find the relative mass/mass of each different piece of hardware

This was a question based on the lesson we did the last Monday, which at this point was almost a week and a half earlier. I could remember doing this type of problem but I couldn't remember how to solve it. It was good we reviewed this because this type of problem is actual quite simple. You just have to divide the smallest mass by all the rest of the masses. So for this problem it was the washers mass divided by all the rest. For the anchor you are given the relative mass, so to find the mass you'll need to multiply that number (3.00) by the washers mass (1.74). That gets you the anchors mass.

This week I think I participated less then last week, but I think that was because there was less to participate in. I worked with my table mates on sheets given to us, and I calculated some numbers for Dr. Finnan, but I didn't take that much initiative to speak out answers with the class. I think a goal of mine will be to share more with the whole class, not just my table group.

But although I didn't participate as much as I could have, I still understood the material. The conversions made sense to me, along with (after reviewing it) the relative mass problems. What gave me some trouble was finding the molecular formula. I understood how to do it, the problem for me was remembering how to do it when I didn't have an example to follow. This was something I should have reviewed for more because I'm pretty sure I skipped a step when trying to solve it on the test. Because of this, I would rank my understanding as a 9 out of 10, because for the most part I understood the lessons this week, it was just that small piece that gave me trouble.

SG Chem 2 - Fourth Blog

This week in Chem 2 we were introduced to a new unit of measurement that is used often in chemistry. This new unit is called a mole and can represents 6.022 x 10^23 atoms/particles. We were also reminded of that fact that atoms combine in simple, whole-number ratios. We learned/re-learned  these two things separately but then later in the week we were able to bring both pieces of information together to solve certain problems that were given to us.

For example, on Monday we learned the basic concept of what a mole was. We completed a sheet that started us out with units of measurement that we already knew, such as a dozen eggs. Then, after solving problems with the dozen eggs the sheet applied what we knew about that to teach us how to calculate things with moles.

On Wednesday and Thursday we did a lab the involved combining zinc and chlorine. We combined the two elements then slowly evaporated the water (that was brought into the reaction through heating) away to get just the combination of zinc chlorine. By doing this we found that the mass ratio was approximately a 2:1 ratio. Each table, no matter how much zinc chloride they had, got the same ratio.

The zinc and the 3M HCl before combining

The Zinc and 3M HCl chemically reacting once combined

The chemical product of the combination of zinc and 3M HCl to form zinc chlorine
(Being put on ring stand to heat away any water)

The chemical product of zinc chloride when heated to get rid of the water

We took the information from the Monday worksheets and the results from the lab on Wednesday/Thursday to complete Unit 5 Worksheet 2 with sample containers. This sheet involved finding the amount of moles or atoms in a certain amount of a given element. For example it asked us how many moles of table sugar were in bottle two (sugar in bottle 2 = 118.6g). Because we know that 1 mole is the elements atomic mass (from the sheets on Monday) and that atoms/elements combine in whole number ratios (from our lab) we were able to calculate the amount of moles in each elements. We could even go farther and find the amount of atoms in the in the given element based on how many moles there were because 1 mole is 6.022 x 10^23.

I think this week I participated more in class. I took leading rolls in our lab that we did and I worked on asking my table mates for help when I didn't understand things. I also am trying to help my friends in the other chem 2 class (fifth hour) who are confused on things that I understand.

I think I definitely understand this unit and the things that we did in class a lot better than anything we did in unit four. That being said, I still need to work on the calculation problems. I understand the simple ones and I understand the concept of bringing down the unit so they can cancel out. What's hard for me is when the problem starts giving a lot of details with a lot of different units and lots of numbers. For example the last few questions that were on the homework sheet. They give a lot of detail and I'm unsure of how to know which ones to use and how to use them. Because of this I would rank my understanding of this week as an 8/10. 

SG Chem 2 Third Blog - 10/02/15

This week in Chem 2a we reviewed and finished up Unit 4 and then started learning Unit 5. On Monday and Tuesday we did a lot of white boarding, mainly consisting of two review sheets.

Review Board A

Review Board B

For many of the questions, the table groups were not able to come up with a single answer that we all understood as correct. For those questions, we decided to have class discussions to help us find and understand the right answers. For example, question three asked us to draw a mixture and a compound of CO2. The table group with board A drew the mix of CO2 as single carbon and oxygen particles (both monatomic), while the table group with board B drew the mixture as one carbon particle (monatomic) with two oxygen particles bonded together, creating a diatomic. Every other group had some variation of either board A or B. The question we had to figure out was, "Which one was correct?" This had rather a simple answer. After some discussion and help from Dr. J we found that oxygen was a diatomic and therefore board B was correct in having two oxygens combined together. 

Although this discussion was a brief one, it helped remind me that oxygen was diatomic and I was able to remember that on the test. The thing I forgot was that there was multiple elements that are diatomic so on the test I forgot to mark hydrogen as a diatomic. But now I understand what I did wrong and I'll be able to fix that mistake in the future.

Wednesday was our test day. I felt okay about it, but the hardest part for me was getting the right definitions of a mixture, compound, element, pure substance, etc. I studied them but I only memorized a definition I had written on a sheet, I didn't really understand the difference between them. This came to hurt me when taking the test because those specific definitions were not on the test and therefore I was rather confused and unsure of what was correct. 

On both Thursday and Friday we started up Unit 5. We started with a sheet called "Relative Mass" which dealt with finding the mass of different items (washers, hex nuts, and bolts) inside a container. We weighed the entire thing, box and all, then subtracted the mass of the box from each item to get the weight of the items by themselves. Then with that information we could find the mass of a single washer, hex nut, or bolt. By knowing the mass of each individual item we could then solve problems and answer questions about it, which is what we did. The main idea from this lab was that you can count the amount of items in a container (bag, box, etc.) by weighing. So far I think I'm going to like this unit better than Unit 4 mainly because the math makes sense to me. 

SG Chem 2 - Second Blog 9/25/15

For me the material we were started learning during this week in Chem 2a was a lot harder to understand than last week. We started going over brand new information about things like compound formulas and ratios (Unit 4 - Worksheet 3). I was not able to/still am unable to understand how to come up with the right answers to most of the examples on the sheet and am slightly overwhelmed about having to do it on the upcoming test. I think my main confusion is that I don't understand what all the numbers we're given (the mass of each element) and the numbers we find (the masses over each other) represent and how to use them to solve the question. I also don't understand what it means the difference between "Atoms of C and O have the same mass" and "Atoms of O are heavier than C atoms by the ratio compound in A."

Another thing that we did was we learned about different scientist from the past, including Empedocles, Democritus, Joseph Priestley, Antoine Lavoisier, John Dalton, and a couple more. We were first introduced to Priestley and Lavoisier through a video we watched in class. It compared the work of Priestly to Lavoisier and described how both were key components in discovering elements and that the thing scientists used to describe the chemical reaction in a substance, phlogiston, was not an accurate description of the change. I found this video very interesting and liked the fact that even though the two scientists had very different approaches to finding an answer, they both needed each other in order to make this new discovery.

To learn about the other scientists we got a sheet called "Matter." The sheet titled "Matter" explained the evolution of what scientist defined as matter.

Empedocles believed matter was made up of four main elements, water, fire, earth, and air, yet there were many flaws in this explanation of matter. Democritus helped shore up some of the flaws by creating a new theory. His theory was that everything was created out of pieces of matter so small that they could no longer be cut in half, he called this things atomos. He also believed that each material or substance had its own, specific type of atomos, and that two different things would not have the same type of atomos. I was really impressed at how people were able to make theories and discover these things with so little technology, just by what they were witnessing happening around them.

In class we started a experiment with a tool that would eventually separate two substances apart. We watched on logger pro as the graph started to resemble that of the heating curve of water. We were unable to finish the experiment in class but I found it interesting that you could separate the two substances because they had different boiling points. I'm not sure if I fully understood what the experiment taught us, but I think after discussing it some more with the class the main point will become clear.

I think over all this week was a lot harder for me to understand the material we were learning in class.  I realize I need to find a way to get an understanding of the lesson otherwise I will be more confused further down the road. 

SG Chem 2 - First Blog 9/18/15

     This week we learned about the difference between atoms, particles, and molecules, along with the difference between pure substances, elements, mixtures, and compounds. To do this we did worked in table groups on a sheet called the "Classification of Matter." The front page showed nine boxes with different shapes inside them. Each individual shape represented an atom, then atoms were combined together (by a chemical bond) to form a molecule. The amount of molecules in the area represented the number of particles in each box. After identifying each of these things we figured out which boxes were pure substances vs. which were mixtures and which boxes were elements vs. compounds.    
     Last year in Chem one,  my class was able to get to unit four, because of this I vaguely remember completing this sheet but I realized I had forgotten a lot of the information in this lesson. I found it helpful to go over the information again and the picture examples (the boxes on the front) really helped me get a better understanding of what each part was and how they connected to each other.
     One thing I find difficult to remember is the which type of atoms are compounds and which are mixtures. I can't remember if it's compounds are the ones that use "&" or if they are the ones that are "squished" together (vice versa with the mixtures). Another thing that I still struggle with is taking the information we learned about the difference between mixtures, compounds, elements, and pure substances and applying them to example pictures, such as what we did on the back of Unit 4 Worksheet 1. I was able to identify everything in the first row of boxes, but once I got to the second row, when the atoms starting forming shapes and condensing together, I got a little confused on which category each box would go into. I think with a little more practice I will be able correctly identify each category.
    An interesting experiment that we did in class was we took a sugar cube and put it in water, then we took another sugar cube and placed it in ethanol, then we took the last sugar cube and put it in a mixture of ethanol and water. We observed what happened to the sugar cubes in each liquid. In the water the sugar cube started to dissolve, in the ethanol the sugar cube sustained its form, and in the mixture some of the cube dissolved while most of it stayed intact. We learned even after a year the sugar would still stay in that form. 

Before

After

      I believe I participated a decent amount in the class, mostly in the table discussions. I try to help my table members when they need help and I contribute when I can. Sometimes when I don't understand a concept or am unsure of an answer I don't add my ideas to the conversation as much because I'm not sure what to say.